Proprietary differential banded gas seal eliminates residue build up and makes chokes easy to remove and install; Integrated spring suspension holds the seal tight, yet allows expansion against the barrel wall for a perfect fit and a smooth transition for shot column entering choke; Gas is controlled at the interface between choke and where it seats in the bore; Extended length tube is easy to change and adds approximately 3/4 inches to the overall length of the barrel; Gas is controlled at the interface between choke and where it seats in the bore; Patterns tighten consistently and reliably